1. Field of the Invention
The present invention relates to a fixing member, a method of producing the fixing member, and a fixing device. This fixing member is used for fixing a toner image on a sheet in a copying machine, a printer, a facsimile machine, and a multifunction peripheral (MFP) comprising a plurality of these functions.
2. Description of the Related Art
Conventionally, a fixing device by which a toner image is fixed on a sheet (recording material) by heating and pressurizing the sheet on which the toner image has been formed has been employed in image forming apparatuses such as copying machines and the like. For the purpose of enhancing a function of the fixing member used in such a fixing device, it has been proposed to devise a surface layer of the fixing member.
In Japanese Patent Application Laid-Open No. 2004-101970, for the purpose of preventing toner from transferring from the sheet to the fixing member (enhancing a toner releasing property), it has been proposed that many grooves along its lengthwise direction are formed in a circumferential direction on the surface layer of the fixing member.
However, in the technique described in Japanese Patent Application Laid-Open No. 2004-101970, the surface layer of the fixing member is ground down and an initial groove shape cannot be kept as fixing processing is repeatedly performed. Consequently, it becomes difficult to keep the toner releasing property over a long period of time.
Thus, adding filler particles to the surface layer of the fixing member may be conceivable. In Japanese Patent Application Laid-Open No. 2007-304374, although the purpose is not enhancing the toner releasing property but enhancing a heat conductivity of the fixing member, it has been proposed that carbon nanotubes or carbon nanofibers is added as a filler to the surface layer of the fixing member.
However, when a whisker-shaped (rod-shaped) filler is added to the surface layer of the fixing member as described in Japanese Patent Application Laid-Open No. 2007-304374, the present inventor has found that a problem may occur depending on how to add it (orientation of the filler).
In detail, it is not specifically described how to add the filler in Japanese Patent Application Laid-Open No. 2007-304374, but the present inventor has found that, for example, when the filler is randomly oriented, it is likely to occur that a chemical affinity between the surface layer of the fixing member and the toner is increased and the toner releasing property is lowered.
Therefore, when the filler is randomly oriented in the surface layer of the fixing member, an amount of the toner that transfers from the sheet to the fixing member may be increased and an image quality may be decreased.
As described above, when the whisker-shaped (rod-shaped) filler is added to the surface layer of the fixing member, it becomes difficult to enhance the toner releasing property, depending on how to orient the filler.